The present invention relates in general to an axial sealing structure of a scroll compressor, and more particularly, to an axial sealing structure of a scroll compressor with a floating seal member, capable of both simplifying and reducing the difficulty of the assembling procedure of the scroll compressor. Thereby, a scroll compressor has a better product quality and a lower production cost.
A typical scroll compressor includes a fixed scroll and an orbiting scroll. The orbiting scroll revolves about the fixed scroll. The fixed scroll and the orbiting scroll each has a spiral wrap inter-fitting each other to allow working fluid entering a compression pocket through a suction port. The continuous revolutions of the orbiting scroll compress the working fluid until the working fluid is discharged from an inner discharge port of the fixed scroll. During the compression process the volume of the working fluid is reduced while the pressure thereof is increased. Axial force, radial force and tangential force appear in the compression process. The axial force tends to cause axial separation of these two scroll members. The radial and tangential forces generate biasing torques. The axial, radial and tangential forces cause leakage from the end panels or the side surfaces of the wraps. How to enhance the volume efficiency of the compressor has thus become an important topic in this field.
A conventional axial sealing structure of a scroll compressor, for example, U.S. RE 35216, comprises a fixed scroll member with an annular cavity formed on the back thereof inside which an annular floating seal member is disposed. The floating seal member has at least one outer lip seal attached the outer wall of the annular cavity and at least one inner lip seal attached the inner wall of the annular cavity. A working fluid under an intermediate pressure flows from a compression pocket into the annular cavity through an orifice and builds an intermediate pressure inside the annular cavity. The fixed scroll member is thus axially biased against an orbiting scroll member by the forces created by discharge pressure acting on the central portion of the fixed scroll member and those created by intermediate pressure acting on the bottom of the cavity. The axial sealing is thereby achieved.
However, there is a problem still existing in the conventional axial sealing structure. Because the floating seal member is inserted downward into the annular cavity on the back of the fixed scroll member, both the outer lip seal and the inner lip seal secured to the floating seal member are flipped upward. But, the outer lip seal is to isolate the intermediate pressure working fluid from the low pressure working fluid. The outer lip seal has to be disposed downward to have its isolating function. Therefore, after the installation of the floating seal member, the outer lip seal has to be further reoriented downward. To simplify the assembling procedure for increasing the production speed, it is therefore necessary for manufacturers to design a special tool. The special tool is able to hold the outer lip seal downward and to deform the outer lip seal for decreasing the circumference of the outer lip seal. The special tool holding the outer lip seal and the floating seal member are simultaneously inserted into the annular cavity. The special tool is then withdrawn from the annular cavity. In summary, although the conventional art can produce a scroll compressor with a floating seal member, the manufacture procedure thereof is tedious and complicated. The conventional art has to consume a longer labor hours to produce a scroll compressor with a floating seal. The fabrication cost of the conventional art is inevitably high.